| 摘要 |
PCT No. PCT/GB94/01923 Sec. 371 Date Mar. 14, 1997 Sec. 102(e) Date Mar. 14, 1997 PCT Filed Sep. 5, 1994 PCT Pub. No. WO95/06518 PCT Pub. Date Mar. 9, 1995The present invention relates to polymer-based gas-containing contrast agents in which microbubbles of gas are encapsulated by non-polymerizable wall-forming block or graft copolymer surfactants. The polymer surfactants are preferably biodegradable and include block and graft copolymers containing linkages of formula (I):-(O)m-CO-O-C(R1R2)-O-CO-(O)n-(I)where R1 and R2 each represent a hydrogen atom or a carbon-attached monovalent organic group, or R1 and R2 together form a carbon-attached divalent organic group and m and n are each zero or 1. |
